Nothing kills a late-night craving like a refrigerator raid. That’s when a hoagie or a piece of pizza really hits the spot.

But a new study confirms what some experts have long suspected: Eating around the clock can contribute to obesity, diabetes and other health problems. A new study by researchers at the Salk Institute for Biological Studies in California suggests that eating only during a 12-hour period can help maintain a lean figure.

Here’s how they tested the idea in mice: Scientists let some of the animals eat at all hours. Other mice ate only at certain times — usually 12 to 15 hours a day.

The results were dramatic. The mice that ate around the clock got obese and had problems with metabolism. The ones that ate only during certain hours were much leaner and healthier. Researchers also made other notable findings: Some mice that were taken off the all-day eating eventually lost weight. Others were much more muscular just because they didn’t eat most of the day.

So here’s what this could mean for humans: Limiting the hours that you eat may be a very effective way to control your weight, and could perhaps even reverse the effects of Type 2 diabetes.

There’s also good news for the weekend cheaters. The researchers found that eating for longer periods of time on the weekends didn’t cause a big weight gain — as long as eating hours were controlled the rest of the week.

Researchers will now test the weight-control strategy in humans, and they expect similar results. They believe that when you eat could ultimately prove to be as important as what you eat. So, for now, keep an eye on the clock every day. After 12 hours, it’s time to keep the refrigerator door closed. That piece of pizza will still be there tomorrow.